| Background: Squamous cell carcinoma represents 90% of all cancers in the head and neck. The lymph node status of the neck determines to a large extent the prognosis, and the classification of the neck as N0, N1 or N2 is decisive for treatment planning. Based on the nodal status decisions are made with respect to (type of) neck dissection and radiotherapy. Preoperative assessment of the neck is, however, not very accurate. In spite of the excellent anatomical detail depicted at computer tomography (CT), and the superior soft tissue discrimination of magnetic resonance imaging (MRI), ultrasound guided fine needle aspiration cytology (USgFNAC) appears to be superior over all other modalities. But even when USgFNAC is applied as diagnostic tool, about 20% (14/77) of patients with negative cytology still develop a neck node metastasis. There are three major reasons for false negative USgFNAC: 1) the tumor-containing lymph node is not aspirated because of its localization or size, 2) tumor cells from a tumor-containing lymph node are not aspirated by sampling error, and 3) the number of tumor cells aspirated is too small to be detected by routine cytology. Recent progress in the detection of tumor cells using microsatellites or mutations in tumor suppressor genes as markers suggests that the sensitivity of USgFNAC can be improved when molecular markers are applied to analyze the aspirate. The accuracy of the USgFNAC could be improved further by innovative ultrasound techniques and/or combination with the identification of sentinel nodes, the lymph nodes with the highest risk to harbor metastases. Aim of the project: To improve the sensitivity of USgFNAC by 1) improved analysis of aspirates by molecular genetic markers, and 2) improved selection of suspected lymph nodes using innovative ultrasound technology in combination with the sentinel node procedure. Plan of investigation: Retrospective. From the last 5 years 32 neck sides were diagnosed by USgFNAC as (false) negative as histopathological analysis of the elective neck dissection specimen showed that (micro)metastases were present. In a second group of 77 patients who underwent USgFNAC, the neck dissection was omitted based on the negative cytology findings. In total 14/77 (20%) developed a lymph node metastasis during follow-up, but with severe clinical consequences as 4/14 patients could not be salvaged. The indicated patient groups will be included in the study together with matched control groups. DNA of microdissected tumor tissue will be amplified by PCR and sequenced for p53 mutations as well as analyzed for microsatellite alterations. DNA of archival cytological smears will be amplified by PCR and screened for the presence of tumor cells by tumor-specific p53 mutations or microsatellite alterations as marker. Prospective. In 80 N0 patients with a carcinoma in the oral cavity/oropharynx eligible for staging of the neck by USgFNAC, 99mTc labeled albumin colloid will be injected adjacent to the tumor to select the sentinel node by planar scintigraphy and handhold gamma probe scintillation counting. The sentinel node and other suspicious nodes will be aspirated by innovative ultrasound detection using 10 MHz transducers, color Doppler or power Doppler. Cytological smears will be prepared and aspirate residue collected. When neck dissections are performed all lymph nodes will be dissected freshly. The presence of radioactive colloid will be analyzed by scintillation counting both in the aspirate residue and/or the nodes of the neck dissection specimen. Tumor cells will be detected by molecular markers. The result of the USgFNAC either by routine cytology or molecular assessment will be correlated to the clinical outcome during follow-up or to the histopathological findings in elective neck dissection specimens. Sentinel node procedures as well as novel ultrasound methods to improve the selection of suspected nodes will be evaluated. Possible results: To improve the staging of head and neck cancer patients by an optimized and more sensitive detection of squamous tumor cells in US guided fine needle aspirates of cervical lymph nodes. As a consequence, the upstaging of the neck from N0 to N1 or N1 to N2 will have direct implications for the therapeutical management of head and neck cancer patients. |
